Electrostatic discharge (ESD) or other causes of error can cause a variety of problems in handheld devices such as cellular phones, camcorders, MP3 players, DVD players, or any other suitable portable device. Many such devices may incorporate multiple integrated circuits such as a main processor and various coprocessors. For example, cell phones that employ cameras may include, for example, multiple integrated circuits. By way of example, a graphics and multimedia coprocessor such as an Imageon™ sold by ATI Technologies Inc., 1 Commerce Valley Drive, Markham, Ontario, Canada, may be used with other suitable coprocessors or processors. High energy ESD pulses generated by the human body or other source can cause LCD panel images to get corrupted, flicker, freeze, fade, or cause other malfunctions in the apparatus when such coprocessors are effected by ESD events.
In the instance where the handheld device includes telephone circuitry, such as cell phone, ongoing calls can be dropped or the device may not respond to a user pressing keypads or activating another user interface. Susceptibility to electrostatic discharge damage can impact market capture and revenues generated by handheld device manufacturers. Therefore, ESD detection and recovery mechanisms have become increasingly important.
Some known techniques for detecting malfunctions caused by ESD or other cause include, for example, a host processor such as a CPU that utilizes a software driver executing thereon to poll critical registers of critical operational blocks within a separate processor. For example, a status register of an external processor may be polled by the CPU via one or more suitable bus interfaces. Status bits such as phase lock loop clock enable bits can be monitored. If the bits show that the clocks have been disabled, the CPU determines that an ESD condition has occurred. However, such a system can be costly in handheld devices in terms of the power usage since the host processor needs to be used for the detection operation.
In addition, systems also typically rely on the host processor interface to also not be susceptible to this same ESD event that caused the problem in the coprocessor. To recover from the detected ESD event, the host processor typically updates the important registers with, for example, an image of the registers stored in system memory, or issues a software reset or a hardware reset to the corrupted subsystem.
In some systems, the system may also automatically update critical registers every few seconds with a stored backup of the information to provide an automatic recovery mechanism even though no error occurred. However, this can utilize unnecessary amounts of power when the device is battery powered. Also, such systems often do not provide any detection mechanism.
Another solution may be to have the host processor monitor external signals on a bus, for example, as opposed to looking at registers in the coprocessor and then generating a coprocessor reset when the CPU detects unexpected information on the external signals on the bus or other pin. However, such systems will not detect all corruption cases since only a few of them would result in external pin state changes.
Accordingly, an improved error detection apparatus and/or recovery apparatus that overcame one or more the above drawbacks would be desirable.